Tissue properties of the human vertebral body sub-structures evaluated by means of microindentation

Dall'Ara, E.; Karl, C.; Mazza, G.; Franzoso, G.; Vena, P.; Pretterklieber, M.; Pahr, D.; Zysset, Philippe (2013). Tissue properties of the human vertebral body sub-structures evaluated by means of microindentation. Journal of the mechanical behavior of biomedical materials, 25, pp. 23-32. Elsevier 10.1016/j.jmbbm.2013.04.020

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Purpose

The better understanding of vertebral mechanical properties can help to improve the diagnosis of vertebral fractures. As the bone mechanical competence depends not only from bone mineral density (BMD) but also from bone quality, the goal of the present study was to investigate the anisotropic indentation moduli of the different sub-structures of the healthy human vertebral body and spondylophytes by means of microindentation.

Methods

Six human vertebral bodies and five osteophytes (spondylophytes) were collected and prepared for microindentation test. In particular, indentations were performed on bone structural units of the cortical shell (along axial, circumferential and radial directions), of the endplates (along the anterio-posterior and lateral directions), of the trabecular bone (along the axial and transverse directions) and of the spondylophytes (along the axial direction). A total of 3164 indentations down to a maximum depth of 2.5 µm were performed and the indentation modulus was computed for each measurement.

Results

The cortical shell showed an orthotropic behavior (indentation modulus, Ei, higher if measured along the axial direction, 14.6±2.8 GPa, compared to the circumferential one, 12.3±3.5 GPa, and radial one, 8.3±3.1 GPa). Moreover, the cortical endplates (similar Ei along the antero-posterior, 13.0±2.9 GPa, and along the lateral, 12.0±3.0 GPa, directions) and the trabecular bone (Ei= 13.7±3.4 GPa along the axial direction versus Ei=10.9±3.7 GPa along the transverse one) showed transversal isotropy behavior. Furthermore, the spondylophytes showed the lower mechanical properties measured along the axial direction (Ei=10.5±3.3 GPa).

Conclusions

The original results presented in this study improve our understanding of vertebral biomechanics and can be helpful to define the material properties of the vertebral substructures in computational models such as FE analysis.

Item Type:	Journal Article (Original Article)
Division/Institute:	04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Surgical Technology & Biomechanics ISTB [discontinued]
UniBE Contributor:	Zysset, Philippe
Subjects:	500 Science > 570 Life sciences; biology 600 Technology > 610 Medicine & health 600 Technology > 620 Engineering
ISSN:	1751-6161
Publisher:	Elsevier
Language:	English
Submitter:	Philippe Zysset
Date Deposited:	12 May 2014 09:05
Last Modified:	05 Dec 2022 14:30
Publisher DOI:	10.1016/j.jmbbm.2013.04.020
URI:	https://boris.unibe.ch/id/eprint/45317